1、 ISO 2013 Testing of concrete Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion Essais du bton Partie 11: Dtermination de la rsistance du bton la pntration des chlorures, diffusion unidirectionnelle INTERNATIONAL STANDARD ISO 1920-11 First edition 2013-05-01 Ref
2、erence number ISO 1920-11:2013(E) ISO 1920-11:2013(E)ii ISO 2013 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, inclu
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4、 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ISO 1920-11:2013(E) ISO 2013 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 2 5 Reagents and apparatus . 3 5.1 Reagents 3 5.2
5、 Apparatus 4 6 Preparation of specimens . 5 6.1 Preparing sub-specimens 5 6.2 Conditioning and preparation of profile specimen for chloride testing 6 7 Procedure. 7 7.1 Exposure conditions . 7 7.2 Exposure method 8 7.3 Exposure period . 8 7.4 Determination of initial chloride content (C i ) 8 7.5 Pr
6、ofile grinding . 9 7.6 Chloride analysis . 9 8 Regression procedure and expression of results . 9 9 Test report 11 10 Precision 12 Annex A (informative) Diffusion c oefficients13 Annex B (informative) Core test specimen 14 Annex C (normative) Immersion method for large specimens 15 Annex D (informat
7、ive) Typical equipment and procedure for vacuum saturation 16 Annex E (informative) Procedures of specimen exposure to chloride solution .18 Annex F (informative) Depth int erv als of pr ofile specimen grinding .20 ISO 1920-11:2013(E) Foreword ISO (the International Organization for Standardization)
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13、 is ISO/TC 71, Concrete, reinforced concrete and prestressed concrete, Subcommittee SC 1, Test methods for concrete. ISO 1920 consists of the following parts, under the general title Testing of concrete:Part 1: Sampling of fresh concretePart 2: Properties of fresh concretePart 3: Making and curing t
14、est specimensPart 4: Strength of hardened concretePart 5: Properties of hardened concrete other than strengthPart 6: Sampling, preparing and testing of concrete coresPart 7: Non-destructive tests on hardened concretePart 8: Determination of dr ying shrinkage of concrete for samples prepared in the f
15、ield or in the laborator yPart 9: Determination of creep of concrete cylinders in compressionPart 10: Determination of static modulus of elasticity in compressionPart 11: Determination of the chloride resistance of concrete, unidirectional diffusionPart 12: Determination of the carbonation resistanc
16、e of concrete Accelerated carbonation methodiv ISO 2013 All rights reserved ISO 1920-11:2013(E) Introduction Steel reinforced concrete structures exposed to the ingress of chloride, either from seawater or other sources, need to be durable for at least the intended service life. The possibility of r
17、einforcement corrosion is significantly increased as the chloride level at the embedded reinforcement increases. For this reason, the chloride diffusivity or chloride penetrability of the concrete is an important property to measure and this International Standard sets out a test method that may be
18、applied to specimens cast to assess the potential chloride resistance of a concrete mix. NOTE This test method takes a minimum of 119 days comprising a minimum age of the specimen prior to testing of 28 days, a minimum of one day to prepare and condition the specimen and then 90 days to expose the s
19、pecimen to the chloride solution. Different periods of curing and exposure may be set (and stated in the test report) in order to adjust the test duration. ISO 2013 All rights reserved v Testing of concrete Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion 1 Sco
20、pe This part of ISO 1920 specifies a method for determining the unidirectional non-steady-state chloride penetration parameters of conditioned specimens of hardened concrete. The test method enables the determination of the chloride penetration at a specified age, e.g. for ranking of concrete qualit
21、y by comparative testing. NOTE 1 The aim of the test is to assess the potential resistance to chloride ingress for a concrete mix. NOTE 2 Since resistance to chloride penetration depends on ageing, due to the effects of continual hydration of the concrete, the ranking may also change with age. 2 Nor
22、mative references The following referenced documents are essential for the application of this part of ISO 1920. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1920-3, Testing of conc
23、rete Part 3: Making and curing test specimens ISO 1920-6, Testing of concrete Part 6: Sampling, preparing and testing of concrete cores 3 T erms a nd definiti ons For the purposes of this document, the following terms and definitions apply. 3.1 as-cast surface surface of a concrete element exposed i
24、n the construction works to a chloride environment 3.2 acid-soluble chloride content amount of acid-soluble chloride expressed in percent by mass of concrete 3.3 chloride penetration ingress of chlorides into concrete due to exposure to external chloride sources 3.4 diffusion movement of molecules o
25、r ions under a concentration gradient, from a zone of high concentration to a zone with a lower concentration INTERNATIONAL ST ANDARD ISO 1920-11:2013(E) ISO 2013 All rights reserved 1 ISO 1920-11:2013(E) 3.5 d i f f u s ion c o e f f ic ie nt proportionality between the molecular flux (e.g. rate of
26、 flow of chloride ions) and the concentration gradient in the diffusion equation Note 1 to entry: In this part of ISO 1920, Ficks Law is adopted as a valid mathematical representation of the chloride ingress mechanism. Note 2 to entry: See Annex A. 3.6 initial chloride content, C i chloride content
27、at a distance sufficiently remote from the surface as to not have been influenced by penetration of the chloride exposure solution Note 1 to entry: It reflects the initial chloride content that came from the constituents when the concrete was mixed. 3.7 n o n -s t e a d y s t a t e d i f f u s i o n
28、 c o e f f i c i e n t, D nss diffusion coefficient that takes into account simultaneous chloride binding Note 1 to entry: This reflects the rate of diffusion of chloride into a concrete when part of the chloride is being bound by the cement. Note 2 to entry: See Annex A. Note 3 to entry: The steady
29、-state chloride diffusion coefficient is measured on water saturated samples where chloride diffuses through a thin specimen between two reservoirs of chloride solution, where one reservoir is at a higher concentration than the other. This steady-state chloride diffusion is not covered by this test
30、method. The steady-state chloride diffusion coefficient only reflects the ionic transport diffusion through concrete, as the concrete is unable to bind any more chloride ion. 3.8 p ro f il e g r in ding dry process grinding a concrete specimen in thin successive layers 3.9 vacuum saturated condition
31、 specimen that is vacuum saturated with water 4 Principle A specimen, either a cylinder or cube, is cast and cured in accordance with ISO 1920-3 (see also amendments of the curing conditions in 6.1), for a standard curing period of 28 days. NOTE 1 A curing period of less than 28 days may be set, dep
32、ending on the type of cement and purpose of the test. Annex B gives guidance on the testing of core specimens, where the core may be sampled from a test element, a precast concrete element or a structure. The specimen is divided into two sub-specimens: a “profile specimen” that is used to determine
33、the chloride profile after exposure to unidirectional chloride ingress, and an initial chloride sub-specimen that is used to determine the initial chloride level, C i . This initial figure is taken as the chloride level of the cast concrete. The profile specimen is vacuum saturated with distilled or
34、 demineralized water, coated on all sides but one and then the uncoated face is exposed to a chloride exposure solution. The exposure is achieved by total immersion of the specimen in the chloride exposure solution. NOTE 2 The test can be performed without vacuum saturating the profile specimen in w
35、ater; this should be stated in the test report.2 ISO 2013 All rights reserved ISO 1920-11:2013(E) NOTE 3 The exposure can be achieved by alternative methods, that are: a) ponding the uncoated face of the specimen in the chloride exposure solution; b) inverting the specimen and having the uncoated fa
36、ce immersed in the chloride exposure solution. NOTE 4 The use of large fully immersed specimens is described in Annex C. The standard reference solution is a 3 % by mass, sodium chloride (NaCl) solution, for an exposure period of 90 days. The solution concentration will be kept constant during the t
37、est. NOTE 5 Other concentrations or solutions, e.g. artificial seawater, and exposure periods other than 90 days, may be set. After the specified period of exposure, at least eight parallel layers of the chloride exposed surface are ground off the profile specimen. The acid-soluble chloride content
38、of each layer and the average depth of the layer from the surface of the concrete exposed to the chloride solution are determined. The initial chloride content is determined by grinding a sample from the other sub-specimen and having the acid- soluble chloride content determined. The surface chlorid
39、e content (C s ) and the non-steady-state chloride diffusion coefficient (D nss ) are determined by nonlinear regression analysis using the least squares curve fitting procedure. Because of the high coefficient of variation, approximately 15 % for D nssfor the test, testing of three specimens is req
40、uired and the results reported separately. NOTE 6 The chloride diffusion coefficient varies with the age of the concrete and the period of exposure. NOTE 7 The diffusion test described in this part of ISO 1920 is only valid for a constant initial chloride content. NOTE 8 When precision information i
41、s available for this test, a check on the validity of the two or more results will be introduced plus the determination of the average value. 5 Reagents and apparatus 5.1 Reagents Reagents of analytical quality shall be used. NOTE Unless otherwise stated, “percent” means percent by mass. 5.1.1 Calci
42、um hydroxide, Ca(OH) 2 5.1.2 Chloride exposure solution a) Reference solutionDissolve 30 g of analytical quality NaCl in 970 g of distilled or demineralized water having an electrical conductivity 0,5 mSm 1at 20 C to produce a 3 % by mass NaCl solution. Store it in a clean container. NOTE This NaCl
43、solution has a similar chloride concentration to that of seawater. b) Other exposure solutionsWhere the concentration of the chloride exposure solution is other than that in 5.1.2 a), the concentration shall be recorded and reported. Where a different solution is used, the composition of the solutio
44、n shall be recorded and reported. NOTE 1 Natural and artificial seawater have been used to reflect the exposure of the construction works. ISO 2013 All rights reserved 3 ISO 1920-11:2013(E) NOTE 2 Higher concentrations of NaCl, such as 16,5 %, and shorter exposure periods (e.g. 35 days) may be used
45、to accelerate the development of a chloride profile. 5.1.3 Chloride impervious barrier system A polyurethane or epoxy-based paint or equivalent barrier system highly resistant to chloride diffusion, to be used in sealing the sides of the specimen. 5.1.4 Chemicals for chloride analysis, complying to
46、a national standard valid in the place of use. The reference number of the national standard shall be stated in the test report. 5.1.5 Distilled or demineralized water, having an electrical conductivity 0,5 mSm 1 . 5.2 Apparatus 5.2.1 Water cooled diamond saw 5.2.2 Balance for weighing NaCl and wate
47、r, capable of weighing to an accuracy of 0,1 g. 5.2.3 Thermometer, capable of measuring to an accuracy of 1 C. 5.2.4 Temperature controlled chamber, capable of keeping a temperature of (20 2) C. 5.2.5 Wher e used, a pol y eth y lene c ontainer with airtig ht lid for immersion of the pr ofile specime
48、n. The volume of the exposure solution shall exceed the volume of the specimen by not less than 12,5 ml per square centimetre of exposed surface. A container may contain more than one sample provided the ratio of exposure solution to exposed surface shall be recorded and reported. NOTE During the te
49、st, the chloride concentration of the chloride exposure solution reduces and if the ratio of the volume of chloride exposure solution to exposure surface varies, the rate of reduction will vary with nominally identical concrete. For this reason if a direct comparison of results from different specimens is required, the ratio of the volume of chloride exposure solution to exposed surface should be constant. 5.2.6 Wher e used, pond t o be attached t o pr ofile specimen. The ponds shall have a constant diameter and initial depth
